The present invention relates to a method of acidizing subterranean formations in well operations and, more particularly, to the use of a exothermic reaction to heat a subterranean formation in order to improve the acidization of the subterranean formation.
Acidic fluids may be present in a multitude of operations in the oil and chemical industries. Acidic fluids are often used as a treatment fluid in well operations. These acidic treatment fluids may be used in clean-up operations, stimulation operations, or other operations for oil and gas wells. Acidic stimulation operations may be used in hydraulic fracturing and matrix acidizing treatments. As used herein, the term “treatment fluid” refers to any fluid that may be used in an application in conjunction with a desired function and/or for a desired purpose. The term “treatment” does not imply any particular action by the fluid or any component thereof.
A common problem associated with using acidic treatment fluids in subterranean formations is that certain formation types, for example dolomite formations, may be difficult to acidize. For example, dolomite formations with low temperatures (e.g., temperatures of 200° F. or lower) may, in some instances, not be effectively acidized by application of an acidizing treatment fluid alone. These low temperature dolomite formations may require additional expenditures and time in order to be effectively acidized.
Assortments of alternatives have been developed to acidize dolomite formations at low temperatures. Some of these alternatives may include viscoelastic surfactants that, in certain circumstances, may gel and push the acidizing treatment fluid further into the formation which may increase the range in which the acidizing treatment fluid penetrates the formation. However, these viscoelastic surfactants may still require larger volumes to be pumped for effective acidization due to the retarded reaction rates.